1. Field of the Invention
This invention relates, generally, to string instruments. More specifically, it relates to a variable tension string device.
2. Brief Description of the Prior Art
It is possible to vary the fundamental natural oscillation frequency of a taut and uniform string by either changing the string's length, linear density, or tension. Most string musical instruments produce different tones by either altering string length (fretting) or playing preset and different string gages and string tensions. Although tension can be used to adjust the frequency of a string, it is typically only used in this way for fine-tuning the preset tension needed to generate a specific note frequency.
When plucked, a uniform string in tension will vibrate at some frequency, f. The frequency of a string with uniform mass distribution can be determined by Equation 1 below.
                    f        =                              (                          1                              2                ⁢                                                                  ⁢                L                                      )                    ⁢                                    TL              μ                                ⁢                                          ⁢                      (            Hertz            )                                              (        1        )            
L is the length of the stretched string, T is the tension of the string, and μ mass per unit length throughout the string. The equation demonstrates that fundamentally there are three distinct ways of manipulating vibrating string frequency:    1. Change string length (L)—Holding all other factors constant, a shorter string will produce a higher frequency (pitch), while a longer string will produce a lower frequency.    2. Change string tension (T)—Pulling a string with a higher force (tighter) will produce a higher frequency, while loosening the string will produce a lower frequency.    3. Change string unit mass (μ)—A uniformly thicker string will move slower resulting in a lower frequency, while a thinner string produces a higher frequency.
For example, all three strings depicted in FIG. 1 will produce the same vibration frequency. In practice, however, the one parameter most used to vary string vibration frequencies is string length (L).
Almost every string instruments uses the first method in either fretting the string (guitar, violin, etc.), which creates a shorter string and produces a higher frequency (note). Additionally, different notes can be produced by playing different gage (thickness) strings present on the same instrument, such as in the piano. Usually preset string thicknesses are set on the instrument and do not actively change.
Although the string pitch may be altered by stretching, or “bending”, the string in stringed instruments such as the guitar, which increases string tension, it is not the explicit way to play these instruments. String tension in stringed instruments is usually adjusted to calibrate, or fine tune, the instrument to a preset and unchanging tension.
The bhapang was the only instrument found that exclusively changes string vibration frequency by changing string tension. The bhapang is a single stringed percussion instrument. The string, which is tightened or loosened by the player with a handle, passes through the drumhead absorbing the drum's vibration as the drum is struck. The player can tighten or loosen the string to produce a continuous variation of sounds. Because of this continuous tension transition of the string, the pitch ramps up or down continuously.
It is also possible to automate and control a stringed musical instrument. This is not new concept and many mechatronic devices have been constructed to do so, however, these devices have been constructed and programmed to play traditional instruments that do not alter the string tension to produce sound.
Accordingly, what is needed is a novel apparatus and method for altering string tension to control its free vibration frequency. However, in view of the art considered as a whole at the time the present invention was made, it was not obvious to those of ordinary skill in the field of this invention how the shortcomings of the prior art could be overcome.
All referenced publications are incorporated herein by reference in their entirety.
Furthermore, where a definition or use of a term in a reference, which is incorporated by reference herein, is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
While certain aspects of conventional technologies have been discussed to facilitate disclosure of the invention, Applicants in no way disclaim these technical aspects, and it is contemplated that the claimed invention may encompass one or more of the conventional technical aspects discussed herein.
The present invention may address one or more of the problems and deficiencies of the prior art discussed above. However, it is contemplated that the invention may prove useful in addressing other problems and deficiencies in a number of technical areas. Therefore, the claimed invention should not necessarily be construed as limited to addressing any of the particular problems or deficiencies discussed herein.
In this specification, where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was at the priority date, publicly available, known to the public, part of common general knowledge, or otherwise constitutes prior art under the applicable statutory provisions; or is known to be relevant to an attempt to solve any problem with which this specification is concerned.